Medical treatment of various illnesses or diseases commonly includes the use of one or more medical devices. Two types of medical devices that are commonly used to repair various types of body passageways are an expandable graft or stent, or a surgical graft. These devices have been implanted in various areas of the mammalian anatomy. One purpose of a stent is to open a blocked or partially blocked body passageway. Various physical attributes of a stent can contribute directly to the success rate of the device. These physical attributes include radiopacity, hoop strength, radial force, thickness of the metal, dimensions of the metal and the like. Cobalt and chromium alloy and stainless steels are commonly used to form stents. These materials are commonly used since such materials have a known history of safety, effectiveness and biocompatibility. These materials however, have limited physical performance characteristics as to size, strength, weight, bendability, biostability and radiopacity. It is believed that the use of refractory metal alloys such as molybdenum alloys can be used to form medical devices such as stents which have superior properties to medical devices formed from more traditional alloys such as nickel alloys and stainless steel. Non-limiting examples of such refractory metal alloys are disclosed in United States Patent Publication Nos. 2006/0200225; 2006/0200224; 2006/0264914; and 2007/0077163, all of which are incorporated herein by reference.
Although refractory metal alloys can be desirable to form medical devices, it is difficult to bond such metals together to form medical devices. The bonding equipment used to form the bond between the refractory metal alloy materials is commonly subjected to high temperatures and/or pressures, thus resulting in damage to the bonding equipment.
In view of the current state of the art, there is a need for an improved apparatus and method for forming a bond between refractory metal alloys that resists damage during the formation of such a bond.